counting posts?

[woostar]

Is there a way to count the amount of posts in a thread?

I have a few adsense ads displayed for member not logged in but want to look spammy and want to keep the ratio of posts to ad to a minimum.

Is there a command to do something like:-

if post_count > 1 then display ad
if post_count > 3 then display another ad
if post_count > 6 then display another ad


Thanks in advance.
W.>

i tried:-
<if condition="$post[postcount] > 1">
</if>
but doesn't seem to work

[woostar]

so can this not be done?